Ext.onReady(function(){
    var mainMenuBar = createMainMenuBar();
    var firstPage = bookRoom();
    
    var viewport = new Ext.Viewport({
        layout: 'border',
        renderTo: document.body,
        items: [{
            id: 'viewPortNorth',
            region: 'north',
            border: true,
            autoHeight: true,
            margins: '0 0 5 0',
            items: [ mainMenuBar ]
        },{
            id: 'viewPortCenter',
            region: 'center',
            border: true,
            layout: 'fit',
            items: [ firstPage ]
        }]
    })
});